This invention relates to elastic sheet material, a precursor thereof, a method of manufacturing such sheet material, and to products made therewith.
For well over a century, it has been recognized that shirred fabrics could be made by stretching a sheet of rubber, holding it in stretched condition, adhering a fabric to each side, and removing the restraining force to permit the laminate to pucker, or shirr; see, e.g., U.S. Pat. No. 22,038. Similar processes have been practiced since that date; see, e.g., U.S. Pat. Nos. 3,468,748 and 3,575,782, where elastic cords, strings, bands, etc., are handled in much the same way. In more recent times, elastic strips have been incorporated in such products as the cuffs of disposable surgical gowns, the crotch and waistband area of disposable diapers, etc.
The application of elastic strips to a substrate involves the use of specialized machinery and processes to stretch the elastic, attach it in the desired location, and remove the stretching force; see, e.g., U.S. Pat. Nos. 4,239,578, 4,309,236, 4,261,782, and 4,371,417. While technically feasible, these processes do not lend themselves to simple, continuous, trouble-free manufacturing. The elastic, whether in the form of continuous strips, bands, filaments or prefabricated composites, is stretchy and hence difficult to handle. Prior to the present invention, it is believed that no solution has existed for this vexing industrial problem.